The androgen-regulated epididymal sperm-binding protein, human β-defensin 118 (DEFB118) (formerly ESC42), is an antimicrobial β-defensin
The androgen-regulated epididymal sperm-binding protein, human β-defensin 118 (DEFB118) (formerly ESC42), is an antimicrobial β-defensin
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DOI：
10.1210/en.2003-1698
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发表时间：
2004-07-01
期刊：
影响因子：
4.8
通讯作者：
Hall, SH
中科院分区：
文献类型：
--
作者：
Yenugu, S;Hamil, KG;Hall, SH
精子在通过附睾近端区域时与各种蛋白质结合，在那里获得向前运动和可重复性。最近的证据表明，某些结合精子的附睾特异性分泌蛋白具有抗菌活性，并可能作为先天免疫系统的一部分发挥作用。我们之前报道了ESC 42，现在命名为人类β-防御素118（DEFB 118），是一种精子结合蛋白。在这项研究中，我们证明DEFB 118具有强效的抗菌活性，并且具有剂量、时间和结构依赖性。用10 μ g/ml DEFB 118孵育大肠杆菌60分钟，使细菌存活率降至对照的20%，25 μ g/ml使存活率降至对照的5%。50和100 μ g/ml的DEFB 118浓度分别进一步将存活率降低至小于2%和1%。观察到盐浓度对DEFB 118的抗菌活性的双相效应。二硫键的还原和半胱氨酸的烷基化导致抗菌活性完全丧失。DEFB 118引起E.大肠杆菌和显着的形态学改变，在细菌表面可见的扫描电子显微镜下一致的膜破坏机制的细菌杀伤。与此相反，真核细胞膜不透DEFB 118，如大鼠红细胞溶血试验所示。DEFB 118抑制大肠杆菌大分子合成和膜透性的研究大肠杆菌中的表达与细胞膜水平上的初级效应一致。DEFB 118可能有助于附睾先天免疫，并保护精子免受男性和女性生殖道中微生物的攻击。
Spermatozoa bind a variety of proteins as they pass through the proximal regions of the epididymis, where they acquire forward motility and fertilizing ability. Recent evidence indicates that certain epididymis-specific secretory proteins that bind sperm have antibacterial activity and may function as part of the innate immune system. We reported earlier that ESC42, now designated human beta-defensin 118 (DEFB118), is a sperm-binding protein. In this study, we demonstrate that DEFB118 has potent antibacterial activity that is dose, time, and structure dependent. Incubation of Escherichia coli for 60 min with 10 mug/ml DEFB118 reduced bacterial survival to 20% of the control, and 25 mug/ml reduced survival to 5% of the control. DEFB118 concentrations of 50 and 100 mug/ml further reduced survival to less than 2 and 1%, respectively. A biphasic effect of salt concentration on the antibacterial activity of DEFB118 was observed. Reduction of disulfide bonds and alkylation of cysteines resulted in the complete loss of antibacterial activity. DEFB118 caused rapid permeabilization of both outer and inner membranes of E. coli and striking morphological alterations in the bacterial surfaces visible by scanning electron microscopy consistent with a membrane-disruptive mechanism of bacterial killing. In contrast, eukaryotic cell membranes were not permeabilized by DEFB118, as indicated by the rat erythrocyte hemolytic assay. Studies on DEFB118 inhibition of macromolecular synthesis and membrane permeability in E. coli were consistent with a primary effect at the cell membrane level. DEFB118 may contribute to epididymal innate immunity and protect the sperm against attack by microorganisms in the male and female reproductive tracts.